1. Field of the Invention
The present invention relates to a sheet conveying apparatus capable of conveying a sheet material having a Radio Frequency Identification (hereinafter abbreviated as “RFID”) tag attached thereto, and an image forming apparatus using the same.
2. Description of the Related Art
There has been proposed a sheet conveying apparatus, in which a sheet material has an RFID tag attached thereto capable of performing transmission or reception via radio communications, and further, there have been disclosed applications for such a sheet conveying apparatus (see, for example, Japanese Patent Application Laid-open (JP-A) No. 2002-337426). An RFID tag has been attached to a sheet material; a reader/writer for the RFID tag has been disposed in an original scanner or a printer; and digital data has been read from or written in the RFID tag of the sheet material.
Japanese Patent Application Laid-open (JP-A) No. 2002-337426)
However, a single reader/writer might accidentally perform communications with respective RFID tags of a plurality of sheet materials in an apparatus, and therefore, data could not be read from or written in only a required sheet material.
In recent years, there has been promoted the miniaturization of an image forming apparatus such as a copying machine, a printer or a facsimile, so that there has been developed an image forming apparatus in which a path from the feeding of a sheet material to the discharge thereof is shortened. In this case, a plurality of sheet materials have been conveyed through adjacent sheet material conveyance paths at the same time, thereby raising a problem of simultaneous detection of the plurality of sheet materials.
In addition, if a metallic portion is formed at a position at which the RFID tags are adjacent to each other, there has been a possibility that the reader/writer cannot perform normal communications. This has been because the RFID tag produces a magnetic field at the metallic portion by a radio wave generated from the reader/writer, thereby causing electromagnetic induction, so as to produce an electric current required for reading or writing data, and further, a metal at the adjacent position also produces a magnetic field, thereby eliminating the magnetic field around the RFID tags. In this case, the RFID tag has hardly caused the electromagnetic induction, thereby raising a problem that the communications with the reader/writer becomes impossible.
Therefore, an object of the present invention is to accurately recognize only an RFID tag attached to a sheet material required for reading or writing by a reader/writer, so as to perform stable communications.